1. Field of Invention
This invention relates generally to oral hygiene, specifically to an improved toothbrush for effecting improved oral hygiene.
2. Prior Art
Among the hundreds of diseases that humans suffer, one of the most common is dental caries, or tooth decay, and periodontal disease. These diseases are mainly caused by plaque on the surfaces of teeth and in the grooves (sulcus) between the teeth and the gums. Plaque is a mucus or slime that consists of bacteria and food particles left over from meals and snacks. The bacteria, which are always present in the mouth, multiply, feeding on residual sugars which are left in the mouth after eating. They form "bacteria cities" or plaque which contains acids that attack tooth enamel to produce cavities in teeth. In addition, the plaque also hardens to form calculus, which, when present in the sulcus, irritates the gums, causing periodontal (around the tooth) disease or gingivitis (gum disease) which can result in receding gum lines and eventual loosening and loss of teeth.
The best known prevention of tooth decay and gum disease is regular and thorough tooth brushing and sulcus cleaning. Although almost everyone in advanced societies has a toothbrush, tooth decay and gum disease are still prevalent afflictions in these societies. Several factors contribute to the problems: Some people do not use their toothbrushes properly, some do not brush for sufficient duration, some have trouble seeing plaque and therefore cannot remove it efficiently, while some, especially children, dislike brushing so much that they brush infrequently.
A few special toothbrushes have been designed in the past in attempts to help improve brushing habits. U.S. Pat. No. 3,261,978 to Brenman (1966) shows a toothbrush with LEDs (Light Emitting Diodes) or miniature light bulbs in the head or handle to illuminate the transparent back side of the head. But because the light from the back of the head shines away from the bristles, it cannot illuminate the teeth and plaque while brushing to improve brushing effectiveness. U.S. Pat. No. 4,779,173 to Carr et al. (1988) shows a toothbrush with light conducting optical fiber "bristles" illuminated by light projected against the roots of the bristles by a light source in the hollow handle. Because the light is projected at a right angle against the fibers' roots, only a very tiny portion of the light is transmitted through the fibers, resulting in insufficient illumination of the teeth and plaque. Also the individual bristles are relatively thick, precluding them from extending into the sulcus and removing the plaque therewithin.
U.S. Pat. No. 5,030,090 to Maeda et al. (1991) shows a brush similar to Carr's, but with optical fibers bent at right angles within the head so that their roots can be gathered and positioned directly in line with a light source. Because optical fibers have minimum allowable bend radii, and because the fiber bundle is quite thick, the head of the toothbrush must be very thick to accommodate the bend in the fiber bundle. This can significantly impede brushing, especially for small children. Furthermore, optical fiber is stiffer and much more expensive than the type of bristles normally used for toothbrushes. A toothbrush with stiff, expensive optical bristles can be very uncomfortable and uneconomical to use and, again, is unable to clean the sulcus effectively.
Thus these devices either cannot illuminate the teeth and plaque while brushing to improve brushing effectiveness, or cannot produce sufficient illumination without the use of a thick head portion. In addition, some are much more expensive and much more uncomfortable than conventional toothbrushes. Finally, their bristles are too thick to brush effectively.